In addition to the purchasing date, there are 3 more rules:
- End user must buy ne PC with preinstalled eligible version of Vista. Retail versions will not be supported for free update.
- Purchased PC must have valid Certificate Of Authenticity (COA) attached
- Only versions eligible for free upgrade will be Home Premium, Business and Vista Ultimate.
Participation in this program is optional for PC manufacturers, so they might decide not to offer this free upgrade option. But, in past cases, all vendors participated in similar programs.
All this can be changed in near future!