If you have set a restore point to before the time you installed the software, go back to that.
Also run this (free)
Have you run any spyware/adware applications such as SpyBot, AdAware?
In terms of the ram, this depends very much on the usage you have for the machine. My PC has two gig as I do a fair bit of video work and also use it for high-end graphics applications. My girlfriend on the other hand, has a laptop running at 800MHz with a 128 and a 256 ram installed, used only for some surfing and emails, and works just fine for her.