downgrade vista to xp then upgrade back to vista

[nasa8209]

hello,

how i can install back my win-vista basic after i downgrade it to win-xp.
i hav no cd, no tech manual.. actually i lost my recovery during formating xp.

Laptop spec
- Toshiba (Satelite A135-S2336)- P/N: PSAD6U-01800DB
- Processor - Intel Cent Duo
- 80Gb HD
- 512 RAM
- built in Window vista basic
- built in ATI Radeon Mob Xpress Series

i still hav 25 product key. in this case can i get back my win-vista by dl it without pay anything

[Ancient Dragon]

without the CD, you will probably have to take it back to the store where you bought it and have them reinstall vista. Or try this