How full is your hard drive?
You should get quite a bit more life out of that HP - for what you use the computer for, it's plenty powerful enough. If you are running out of storage space, upgrade the hard drive or get an external hard drive.
http://www.crucial.com/store/listpar...vilion%20a530n
For less than $50, you can max out the ram with 2gb.
Do you do any software maintenance - delete temp files, fix registry errors, do antivirus and antimalware scans, chkdsk and defrag, things like that?