Computer has a load of problems?

[Mica]

So very recently my computer has been really wonky.
-songs on pandora skip like a scratched CD
-I can't upload images on flickr
-I can't attach files on yahoo mail
-I can't reblog anything from tumblr
-Some gifs/images don't load on my tumblr dashboard
-Some images on google load wrong or don't load at all

This doesn't seem like the work of a virus, but I'm not too experienced with that kind of stuff. I'm running a scan now.
I know this isn't a problem with my wifi network, because I've connected to several ones and all the problems are still present. I've never had so many problems at once on this computer.

If it helps any, I recently downloaded steam and both portal games, but I didn't think it would impact my computer in this way. I have a 64-bit acer aspire laptop running windows 8
I forgot to add that some weblinks have trouble opening the first time around and that I have a buffering problem on youtube

[The Necron]

Most likely whatever you are using to search things is corrupt, reinstall firefox or google chrome or whatever you have

[Sadsongs]

First thing I'd do is stop or remove any non-essential programs. Monitor CPU and network usage - see if anything shows up there.

[Boss]

Might need a new computer.