very slow performance

I know this gets discussed frequently, and I have looked over a ton of older posts. But cannot find enough good info to apply to this laptop. My teenager's laptop, a Toshiba Satellite series with Vista Home, big HD, 2 Gig RAM, usual stuff, runs extremely slowly. It is slow to boot, slow to open any programs, slow to respond to any mouse action. Overall very slow. I have another Vista Ultimate laptop, and it is a lot faster than hers. Indexing is full, Vista came on it so install over an XP solutions don't apply, have already run typical maintentence stuff like antivirus (Avast), antispyware (AdAware and Spybot), Windows cleanup, Defrag, and ran scan disk which found and fixed two bad clusters in files. Defender is active, and she has the firewall enabled. I had her backup all her files tonight and ran all the utilities again, and thought I might need to reinstall Vista. Before I do, can anyone refer me to a website that can give me more ideas to try and get this thing up to speed?