Windows 7: Browsers cannot start (just a ~2mb .exe)

Hi,
anyone recognized the following crazy phenomena?

When I click on a browser, nothing happen, just a ~2mb exe started (doesn't matter it is Opera or IE8). When I 'End Process' it in TaskMan, and click on again the browser, nothing happen again. Sometimes I do this 10 times maybe...
Jsut a f****g ~2mb exe, and nothing happen. After clicking on it many times, at one point, it starts... (?)
Sometimes it started normally, at first time when I click on it....
And I can't figure out any relation to this behaviour to the system; check trojans, viruses, etc, cleaned forth-and-back the OS with Optimizer/Cleaner softwares, but NOTHING!
This is drives me crazy now more and more often.

Any idea would be great!
Thanks

Since the problem is common to IE and Opera, maybe it's a Windows issue and not a browser problem. Two things I do to repair Windows which don't require a Windows disc are:
c: /properties/Tools/Error Checking, and
command prompt>sfc /scannow
(Do each one separately, the first will run at the next boot while the second will run right away but takes a while to complete.)

Which so called "Optimizer" Software did you use? Roncerr gave you great advice, but I would just like to chip in and say that running ANY sort of optimizer software on Win 7 is at best useless, and at worst an OS killer.

The only thing that I would even give the time of day to, is probably the most highly respected App in the technological world, Crap Cleaner, which basically does a more thorough version of Windows' Disc Cleanup (assuming that's the only bit you use of course) Piriform - Download CCleaner, Defraggler, Recuva, Speccy - Millions of users worldwide!

Thanks guys, I will do roncerr's advice.

I experience this problem for several month, and I had iolo SysMech (my license has expired a motnh ago, and I did'nt renew it) so that was one cleaner/optimizer software. After this I installed CCleaner and Comodo's System Cleaner.
None of these "cleaners" solve this annoying phenomena.
And yes, you're right, probably it's not browser issue rather OS, but I experience this problem only with IE and Opera, that's why I asked it here.

Ahmm, khm... You mean what under this:
c: /properties/Tools/Error Checking
Sorry, but what's this? Where should I find this "thing"?

Right-click C partition on the left side of Windows Explorer (or right, doesn't matter), and then go to Properties - Tools - Error Checking...

Baaaah, ok. Thanks.