Amil,
You just might be in luck. McAfee, or "MucAfee", as one of our more renouned members put it, is a resource hog and hard on Windows 7. It is a poor quality antivirus, and no one had to pay me to say that. If you decide to remove it, use this tool (as most antiviruses leave files behind unless you use an uninstaller tool):
|MG| McAfee Consumer Product Removal Tool 5.0.285.0 Download. You will need to download and run it. It lists at least 3 download locations, choose any one.
If you would like another, more slimmed down antivirus program, you might be interested in
Microsoft's Security Essentials. If not, there is a whole thread on many different antiviruses, and you might take an interest in the discussions:
What's the Best Anti-virus?
Aside from that, here is a tutorial on how to speed up and refine windows without having to download anything:
Optimize Windows 7 -
tutorial created by Brink