I use SharpDevelop on a laptop that is too old and under-powered to host Visual Studio, and while I have had the occasional crash, I have also been able to use it for long periods of time, doing some non-trivial C# development work. So, I'm surprised to hear that you've had such difficulty. For what it's worth, I'm using XP Home and .NET 1.1.
SharpDevelop blows. Two reasons:
1. it wipes out code without any warning. for exmple, changing the type of a variable, say, a textbox. this resulted in the textbox being erased from the form, along with the code. unbelievable.
2. no debugger. wow.
I will report whether or not I'm more successful at the second computer I try it. Both WinXP/SP2 though. Good to know Adam that SharpDevelop indeed can be used for longer times without crashing.
Microsoft has also some free tools that you can use to develop applications and websites.
One of the things lacking is the ability to work with multiple projects in a solution.
So said Casual Jim in the comments to the post in which I linked this entry.