Help Me

Hi, i need some help,  when i try to run certain programs a shell.dll 32 error pops up.  and sometimes if I am online, my computer pops up with a blue screen saying bad pool caller (with a bunch of other stuff) and then turns off. and then today, i can't get one of my internet email log in pages to even load it just says page cannot be displayed.  it is mail.mwisp.net. if someone else could try so i know if it is my computer or their problem... any help with any of this would be great.  thanks