320 MB seems woefully little - 256 + 64. Add more.
Windows Defender (free) will show you rubbish in the Start Up list and any phantom programmes that may be eating cpu/memory resources - you can remove any that are suspicious or unwanted. CCleaner has a feature to tidy up the registry. Spybot Search & Destroy (free) will remove spyware.
Peccavi
January 2009