1. Very unlikely that the Toshiba Tecra will have the same drive connection.
I would expect your HP to be SATA and gthe old Tecra PATA (IDE)
2. Even if it was the same, the drivers for the Toshiba will all be different, all the motherboard driver s etc and therefore EVEN if it boots and runs, you stand every chance of it simply complicating the problem, when and if you ever manage to get the HP booting.
Best advice - go back as per my link and check if the hard drive is listed not in boot priority, but in the system page.
If the MBR and BCD of Vista are corrupted it will not see it as a boot device, but it may well still see it as a hard drive.
If it is seen as a hard drive - although I suspect it unlikely as Ubuntu cannot see it and that does not require it to have any file system, that windows can read, simply recognisable files. - you need to do as I said and get your data off.
It MAYBE that you are facing a reinstall, the trouble being that if the drive file system is now totally corrupted - you may not be able to access any recovery partition.
In summary I would
1. Check BIOS as above
2. Reset BIO(S to default on the link I sent you - see if that helps IF NOT
3. Remove HDD and connect in enclosure or docking station - if you can beg or borrow
3. See it is recogised when connect to another computer.
IF all that fails and the end result is a new hard drive, although we are NOT at that stage yet see this
Back 1800 hrs now 0216