iMac 27" a lot of Finder crashes

[LAS.mac]

I have a 27" iMac, one year old, Lion 10.7.4 (it's the i5, 8 Gb RAM). Since some months, I'm experiencing a lot of system issues. FOr instance, Finder crashes; after a Time Machine backup, the mac is unable to do the incremental one (once it cannot find the disk, the second time it cannot create a directory, and so on); and other similar issues, such as unable to print, etc.
Everything goest back to normal if I restart the mac.
I don't know what to do or check. I did repair permissions and check the disk, but this did not resolve my issues.

I don't know whether this can be something related to Lion, to some hardware component, some legacy software (I got this mac last year in May, with Snow Leopard - and updated later to Lion).

What would you do? Format the disk and do a fresh Lion install and then recover my data from Time Machine? Or check something else first?

Any suggestion is largely appreciated.

 

[Dadioh]

Possibly bad RAM? You can get all sorts of strange behaviour if the RAM is faulty. You can download and use Memtest or, run Apple Hardware Test from your Install DVD.

 

[sebuseb70]

Same problem as LAS.mac

Hello i have an imac I7, 27 '', 3,4 GHz, osX10.7.4 and i have the same problem, finder crashes few times a day, problems with time machine. I have removed recently memory (16 GB of not genuine apple memory) and put back original apple memory. Time machine problem seems to have disappeared but still some problems with the finder when using adobe CS 6.