Speed up my computer
There are two well-proven strategies for speeding up your computer:
Add or upgrade resources (better CPU, more memory, faster hard drive, better networking)
Remove programs which consume these resources
And then there are a lot of, how shall we politely say this, less-well-proven strategies. You'll see people suggesting pagefile tweaks, registry hacks and/or 'cleaning', third party disk defragmentation tools, disabling services, and more.
That's all well and good. There's nothing wrong with wanting your computer to run better! But there are two important questions to ask:
What exact performance aspect are you looking to improve?
How will you objectively know that things have improved? (In other words, what actual, systemic, repeatable measurement will show that improvement has occurred? And no, 'it feels faster to me' doesn't really count. The placebo effect is too insidious and well proven for such general impressions to be reliable.)