I'll say good luck. you'll probably need it. (reassuring huh?)
Not that Linux is overly difficult, it's just different enough that things do not seem overly intuitive.
You will find that the programs that you want to use will not work natively under Linux, it may be possible to get them to run using something like WINE or Crossover Office, but nothing is guaranteed at all, let alone 100%.
There is equivalent software, OpenOffice.org (Don't blame me for the name) for MS Office, Gimp for Photoshop and plenty of others, for the most part you'll be able to do what you need to don, but won't have access to every single feature you want.
The biggest obstacle you'll have to overcome though, would be hardware support, for the most part it should be OK.. you might run into issues with thing such as graphics tablets, printers, modems, wireless networking, laptop support whatever.
To get your feet wet, you can download what's called a Live CD, where the actual version of linux will run from the CD, you won't need to affect windows, won't need to install anything and you should be able to see how you like it.. remember that because it's running off CD, it will be slower, if you install it, it will be comparable to running windows XP on the same machine.
2 such Live CDs which are the most popular would be
Knoppix or
Ubuntu It is also possible to install either of these, but if you decide to install the system you'll have other options available to you. Both of these CDs can be download, Ubuntu will ship you a Linux CD free of charge.
But in all honesty, if you're looking for ways to get away from viruses etc. It would be a better option (IMHO) to look at the way you use windows and perhaps make changes there.. you won't have to relearn what you currently know.
You could probably have a large positive effect by Making sure you have a virus scanner running in the background, run frequent spyware scans on your system, use firefox not internet explorer for your web browser and create a non-administrator account that you use for normal day-to-day use. If you're having problems with corrupt files, make sure you have good backups of files outside of your PC (removable hard drive, CDs, etc.)
I don't want to put you off, just make sure you want to switch for the right reasons... switching will take time + effort.. but don't hesitate to ask..