Hello,
I am working on an application, which will ultimately be distributed to end users. My IDE is VS 2010. My application does not use any of the features of the 4.0 framework. Should I then target a lower version of the .NET framework like 2.0 which users in general will more likely to have already installed than the 4.0 framework ?
Thanks
Assuming you don't need any features from anything higher, there's no reason not to target 2.0. It should be forwards compatible with newer runtimes, with a benefit of running on older platforms that don't run newer runtimes.
It depends on who your users are, how likely they are to upgrade just for the sake of your application, and whether you really care whether they use your application :)
If you're not intending to benefit from others' usage of your application and there's not specific reason why your target audience should remain with only 2.0, go with 4.0, particularly if you're doing this to improve your skills.
If you intend to make money from application sales and the upgade requirement is likely to cost you sales, stick with 2.0.