I would check the BIOS config to see/change what dash is default. It may be looking for C:\default.xbe for example, but evox is evoxdash.xbe. Load slayer's again, and ftp in to your box. Checking the locations of each dash(evox, avalaunch, unleashX) so you can specify those locations in the BIOS.
AND...
If you use the 'F: Drive Format' on slayer's it leaves C:\ retail so you can go on LIVE!(with other precautions...), if you choose the C: Format option, it will install the dash you want(evox) in C: which is what you want.
Hope this helps.
DSLTech_Dude