do pc applications run in windows tablets?

Windows tablets come in two flavours. Windows RT - which can only load apps from the Windows Store. Or Full Windows (often called Windows Pro, as that was the name that the Surface Pro tablets used). These tablets run full Windows and so can run ANY Windows programs - from the store or from elsewhere.

Be aware of the space and memory limitations! And some apps are not designed for touch use...

But you can take something like the Dell Venue Pro 8, or the Lynx 7" tablet for under $100, and run photoshop on them - but it is likely to run rather slowly! and you wont actually be able to edit anything, because the screen size is too small - but it will run!

If the tablet is running Win 8.x, then it can run any Windows application. It is a "real" Windows computer just in a smaller case. However, many of the tablets have a low end processor, limited RAM memory and a small hard drive (again because of the limited space in the smaller cases.) You will want to check the specs for the programs (Photoshop, etc.) and make sure that the tablet meets or exceeds those requirements. So tablets will and others will not. It is not an issue with it being a "Windows tablet", but an issue with the hardware in that model of tablet. Each is different.

The Applications is created special for windows tablets. You can't run photoshop and fl studios.

if the tablet is running a full windows OS, then why not?