i did at my last school. it involved (i think) getting the windows software in english and re-installing it. we called the 'computer doctor' and he did everything. i think the biggest hassle is getting the english software. after that, you could probably find the instructions online or i imagine it would be pretty cheap to have the 'doctor' take a look at it.
Generally if you're looking for total english you have to change the operating system to English (a lot of work and requires "the doctor" in most cases.) If you change your operating system some Korean or whatever language you're in might not work or read properly.
If you just want your MS Office or programs in english you'll have to get English versions of Office and remove your current version, then load English Office.
It's expensive and a lot of work. It might be better to remeber where everything is (placement for functions are the same as English versions) or just learn the Korean for what you need.
That's as much as I know on the subject and I'm not an expert. I could be wrong.