Sometimes, no matter what elaborate measures you take – defragging your hard drive, deleting unused programs, updating all your spyware suites - your computer still runs at what seems to be an abnormally slow pace. You may not suspect that your email could be the culprit for even a moment, but clogged inboxes slow computers down far more often than most people realize. Fortunately, the solution to speeding up your computer by cleaning out your inbox is easy: make sure to delete email you don't need anymore, and set up rules to manage your mail.
Delete Old/Unnecessary Mail
If you use Microsoft Outlook, even mail you've already sent is stored in your computer. Whatever email program you use, mail that you have already sent and not deleted but don't need anymore makes checking new mail a much lengthier process than it needs to be.
Go through your Sent box (in addition to your Read/Received box) and delete any old and/or unnecessary emails, particularly those with large attachments (documents, photos, music files, etc.). If you don't have the time to go through your entire Sent box and are sure that you don't need any of the mail you've already sent, you can save time by deleting everything in one fell swoop. All email programs have a “Select All” or “Toggle All” option. Click this, and then click “Delete.” Watch as all the mail on the particular page you have open is relocated to your particular mail program's trash bin, or immediately deleted entirely if you have it set to do so. It's usually a good idea to leave the trash bin settings on default, since this way mail deleted accidentally can be recovered with no trouble.
In most mail programs, there will be an option to View/Show All or Depaginate, which erases the separations between pages of mail and lists all of it in a particular box (Inbox or Outbox, for example) on one screen, to allow for easier deletion. If you know that most of the mail in the particular box you're deleting from is trash, then this is logically the fastest, most efficient option.
Set Up Rules to Manage Incoming Mail
Spam can take up a huge amount of mailbox space, slowing up load times for exterior storage mail programs. If you use another email program, like Gmail, Yahoo, Hotmail, AOL, or any other, use your address book to your advantage. If you know you want to receive mail from only a select few people, add their email addresses to your address book. This way, all the mail from people you don't know (presumably spam) will be filtered and sent right to the trash/spam folder your email service provides. Be sure to always check your spam folder, however, since sometimes important messages may slip through unintentionally (possibly due to changed/new email addresses, etc.). It's always a good practice to skim your spam folder before purging, just in case. Quickly glancing at your spam folder takes a lot less time than going through each email individually and deleting it, and saves space as well, since usually you won't feel like bothering to delete spam in your Inbox until it has accumulated to the point where it is slowing down your loading times and bogging down your storage space.
In the case of Microsoft Outlook, which keeps mail stored on your hard drive, spam and other unnecessary mail can do more than slow up page loading times – it can clog up your entire computer and slow all aspects of it down considerably. Microsoft Outlook can be formatted.
Setting up Spam Rules in Microsoft Outlook
● Click on Tools.
● Click on Message Rules.
● Click on Mail.

In the Message Rules window that pops up, click on New.
A new window
should pop up with three rectangular steps inside. In the first
rectangle, “Select the conditions for your rule”, you should check
the boxes next to:
Where the subject line contains specific words
Where the message body contains specific words
In the next rectangle, “Select the actions for your rule”, click on the box next to Delete it.
In the third rectangle, “Rule Description,” click on the “And” check the box next to Message match any one of the criteria.
Click on one of the two “contains specific words” links that now appear in the Rule Description box (it doesn't matter which one you pick).

A “Type Specific Words” box should pop up. Here is where you can type in words that occur in unwanted emails one at a time, pressing “Add” after each one, effectively adding it to the list.

Type in all the words you want, then press OK.
Now click on the other “contains specific words” link in the Rule Description box, and repeat the process. Once you have typed in all the same words you typed before, press OK.
Microsoft Outlook will now automatically scan all incoming email for the words in the list. When it finds an email containing such a word, the email will automatically be moved to the Spam folder, saving you the trouble of time-consumingly reviewing each one (or procrastinating about doing it), and therefore preserving precious hard drive space on your computer.
Collected spam, already read, and/or other unnecessary email can slow up the load time of your email program, and, in Microsoft Outlook, the speed of your computer in general.Take the easy route to a faster computer: delete large attachments and other unneeded mail, and come up with spam filters or rules for the emails you don't want so that you don't have to deal with them individually. Your noticeably faster page-loading and computer speeds will be a welcome reward.