Virus hidden in restore folder in XP ….. how to remove

Found massive infection removed , only to find that it was also in the system restore 🙁
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Loaded new [ older ] hard drive and rebooted the machine with the original as a slave …..can access all pertanent info …. all is good [ may be ok ? ].
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Works great ……… but can’t stand to be beaten ……. any info about cleaning out the restore folder will be appreciated .
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Thought about trying to delete the infected folder and replace it with the “new” one ….but in case it’s needed it would only have the very basics and no old “important” info.
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Thank you in advance .
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Mike