I purchased. downloaded and burned SpinRite.iso utility on CD. Despite my tinkering with BIOS, I fail consistently to by-pass HD during boot and as a result I cannot gain access to that application. What am I doing wrong? any comments highly valued. Thanks

Do they have an MD5-sum or anything so you can verify it's not corrupt?

How did you burn the CD?

Have you tried burning on a different disk?

I would agree--there could have been an error in the downloaded file/defect in the disc/error by your CD burning app.
Fortunately with Spinrite's license it means-- you can redownload/burn it again-- all you need is your login/license info.

One question --what (program) did you use to burn the disc?

Thanks for reply. I used the Nero app to burn cd

Nero's good--I think something got corrpted during download....or maybe a bad disc-- it does not take even visible damage to throw off a lazer.
I'd try it again. I've had program updates mess up during the DL -- hosed my AV once/had to reinstall.
If you are on broadband-- you could try temporarily disabling your AV-- a minute or 2 on a trusted site should not be a huge risk.
Sometimes AV's can interfere with DL's