hijack this

Hello, I used to run Hijack this on my old desktop computer all the time–no problems. My new laptop cannot open the "HJTInstall" program file though. I get the "Choose the program you want to use to open this file" box popping up, instead of the HiJack this opening up. What program must I use to run this? After I get the file open, I need to send in a log, since my computer is locking up, running slowly, and doing assorted weird things. Thanks in advance!

Pls disregard previous post–I got HiJack this to load, and will post a log file in a new thread. Thanks.