You might have a lot of "crap" on your hard drive than can be deleted. Such as web browser temporary files.
Assuming you are using Internet Explorer 9.
1. Click the "gear" icon in the up right corner.
2. Click on Internet Options
3. In the General tab Browsing history section click Delete button.
4. In the new window that pops up make sure the box for Temporary Internet files is checked. The other are optional.
5. Click Delete button, and it will close that window.
6. Back in the Internet Options General tab, still in the Browsing History section, click the Settings button.
7. Another window opens. Where it states "Disk space to use", but in a relatively low number like 200 for 200MB. Less if you prefer.
8. Click Ok.
9. Click Ok again.
If you are using FireFox 17.0.1...
1. Click Tools in the main menu up on top.
2. Click Options and a window will open
3. Click the Advanced section icon.
4. Click the network tab.
5. In the "Cached Web Content" section click "Clear Now".
6. Check off the "Override automatic cache management" box.
7. Set the cache limit to something small like 200MB.
8. Click OK to close the Window.
To run Disk Cleanup... I assume you have Windows 7...
1. Click "Computer" Icon.
2. Right click the C: Drive
3. Click Properties
4. In the new window click the "Disk Cleanup" icon.
5. A new window will appear. Simply check off all the boxes.
6. Click the OK button. The window will then close.
I am pretty sure you have Service Pack 1 installed on your PC so... the backup files for it can be deleted. Assuming you still have the Properties for the C: Drive still open....
1. Click the Disk Cleanup button again.
2. In the new window click the "Clean up system files" button. A new window will eventually open, you need to wait.
3. This time you should see a box for "Service Pack Backup Files". If it has already been deleted, then there's nothing to delete. Otherwise click the box to clean up around 1GB of speak... I think. It has been a while since I've done it.
5. Scroll down. If your PC has ever crashed, then there may be some "System archived / queued Windows Error Reports" that can be deleted. Click those boxes.
6. Click the OK button.
7. Click the Ok button to close the C: Drive Properties window.
Lastly, there is a hidden temp folder that can have a lot of files in it. Disk Cleanup does not delete the files in there. By default Windows hides system folders from you because if you accidentally delete them you can screw up your Windows operating system. Be very careful...
1. Click "Computer" icon to see the hard drives.
2. Double click the C: Drive.
3. Go into the User folder.
4. Double click the folder with your username / login name.
5. Go into the 1st folder on top called AppData.
6. double click on the Local folder
7. Double click the Temp folder
You likely have a lot of files in here especially if it has been a long time since you had your PC. When you use your PC Windows tends to store a lot of temp files here. Most are no longer being used and can be deleted, but a couple are currently active and cannot be deleted at all. To delete the unused / unwanted files...
1. Sort files by the date.
2. Select all files which does not have the current date.
3. Delete them.
4. Delete all folders as well that does not have a current date.
That's it you're done. I recommend you hid all system folders so that you do not accidentally screw anything up. I recommend you go through this particular process of deleting things in the hidden temp folder once every month or two months.