There are a number of factors to consider when upgrading your operating system to Windows Vista:
Which version of Vista do I require?
Many versions of Windows Vista will be produced for Home and Business users; information for these is readily available on the web.
One thing to be aware of is that:
"Customer review version RC1 is time-limited,
pre-release software that will expire on June 1, 2007"
Source: microsoft website
Are upgrade vouchers valid and redeemable?
The Vista Voucher for Windows XP Pro entitles the holder to upgrade to Vista Business directly from Microsoft. Shipping charges are $15 payable to Microsoft. The invoice must be retained and the system must be purchassed from the 26/11/2006 to 15/03/2006.
Please note that purchasers of OEM Software must fall into one of the categories listed below:
Hardware on an existing PC is being upgraded, which must include basic operational components such as memory or motherboard, therefore the OS software can be upgraded also using OEM software.
A PC is being constructed from scratch.
If the machine is to be resold, whether it is new or second hand, OEM software can be added prior to sale, but the operating system cannot be changed
OEM software can be bought by a reseller with the specific intention of selling on to another Reseller, providing that the sale is accompanied by a hardware sale, such as a hard disk.
As with most things; if it looks too good to be true, it probably is. Everyone likes to get hold of the latest software for a great price, but paying serious money for a demo version which expires, or an iredeemable voucher could seriously spoil your new year!