IE7, in Vista, ph number-eating bug (?!)

Has anyone experienced phone numbers inexplicably disappearing from e-mails and websites when using IE7 as part of Vista? I've seen them disappear seconds after typing them into an e-mail doc. This doesn't happen when using Firefox/Mozilla.

Do I need to reload Vista? Any other ideas?

Thanks - KH
Hi Ken, welcome to NST.
I use Vista 99% in a quad-boot, and until a week or two ago when I downloaded IE8, I occasionally used IE7. 99% of my browsing was done with Maxthon 1, which uses the IE7 engine. 99% of my email is done through Vista Mail.
I've never seen the phenomenon you describe, but if I had, my first suspicion would be a Malware infection.
I'd suggest you start with a thorough scan with as many anti-Malware freeware products as you can locate and download.