Can a Windows virus transfer to Ubuntu?
Your operating system is neither the first code that executes on your computer, nor is it the code with the highest level of access. Malware loaded into the bootstrap code (including BIOS, video BIOS, RAID BIOS, NIC BIOS, UEFI, UEFI modules) not only will not be erased by installation of a new OS, it can hide itself from detection by the OS (although not perfectly, it will slow things down1 and timing analysis may be able to detect that).
Only a small fraction of all malware operates at this level, but multiple cases have been documented. Here are just a few examples:
New BIOS Virus Withstands HDD Wipes
Blue Pill is the codename for a rootkit based on x86 virtualization
Rootkit Detection Framework for UEFIWay Back Machine "UEFI has recently become a very public target for rootkits and malware. Last year at Black Hat 2012, Snare’s insightful talk highlighted the real and very significant potential for developing UEFI rootkits that are very difficult, if not impossible, to detect and/or eradicate. Since then, a couple of practical bootkits have appeared."
Also, Stack Exchange site Information Security has several relevant questions:
How to detect a virus in a network card?
Viruses on video cards?
To be pedantic, these wouldn't be called "Windows viruses", although they may be carried inside Windows malware which served as the infection vector. And they wouldn't be said to "transfer to Ubuntu". My point is that if you had asked the right question, which I feel is "After formatting my Windows partition and installing Ubuntu, might I continue to be affected by malware?", you would learn that the unfortunate answer is "Yes that is possible."
1 But malware that infects a coprocessor, such as the Intel Management Engine which has recently come to mainstream attention due to a critical vulnerability in the way Intel does remote authentication would not spend processor cycles. At best it might cause some timing variances due to bus and memory contention. Malware that infects a management subsystem is basically a worst-nightmare scenario, for both detection and removal.
There are a few parts to the answer to your problem:
Threats don't transfer from one OS to another
Threats that work on Windows usually don't work on other OS (there might be some that do, but I have never heard of any) because they both work very differently. That way, a virus that looks for your C:\Windows\System32 folder on windows won't find it on Ubuntu as it doesn't exist.
Threats don't survive a total wipe of your hard drive
If you erase your hard drive and install a fresh Windows on top, any existing threats would have disappeared, as they are just regular programs. I don't know if best buy employees did a simple rollback to factory settings or a full re-install of windows, but in the case of the re-install, you shouldn't have had any remaining problem.
As a conclusion, no, your viruses won't transfer to Ubuntu. However, your problem might be related to hardware problems. If you still have issues with your Ubuntu, you might want to ask support to look at your hard drive and motherboard and see if there is any problem there.
Note: If you still have viruses after a 1st Windows re-install, you should seriously check if websites you visit regularly are not infected or install a better protection software.
No
If you installed Ubuntu over windows and deleted all the Windows files the virus can not spread.
You can get Windows viruses on Ubuntu if and only if you install Windows software via programs like Wine.