Can a scratched record...

There is a way that works absolute wonders about 20% of the time, improves the lp substantially about 50% of the time, doesn't work at all 25%, and can cause more noise about 5%. It involves spinning the record backwards. You need the right needle, which depends on the type of record and what cutting head was used - and there is also skill/experience involved.

For MANUAL click removal, I use WaveRepair. It's very easy to use, once you're past the "learning curve", and they have a free 30 day trial:

http://www.delback.co.uk/wavrep/

WaveRepairs's AUTOMATIC click removal functions are not that great, though. For automatic, I've been meaning to give this one a try (but haven't yet):

http://www.wavecor.co.uk/