SSD for ancient 965P E6600

My brother is still using my old E6600 rig as his system.
No games to speak of, just the usual internet stuff so it's not exactly working hard.
Trouble is the equally ancient HDD is failing, showing damaged/.missing clusters.
Any reasons not to swap it for a 128Gb SSD?
The MB is a Gagabyte 965p-s3 v3.3 and has SATA 3GBs connections.
I'll probably do a new install of Win 7 rather than try to migrate.